FTP (File Transfer Protocol) is a method of copying files across servers. If you want to copy files from your computer to your web host or from the host to your computer, you would use either FTP or SFTP, the secure version of FTP, if your host supports it. Note that there are other UNIX commands that might be used in some situations, but this is going to be your main option.
FTP is a UNIX command-line, series of commands, but the good news is that there are graphical interfaces to handle this for you so that you don’t have to memorize commands.
One of the most popular GUI (Graphical User Interface), FTP clients is FileZilla. This is free software that supports both FTP and SFTP. It makes using FTP as easy as copying files on your local PC or Mac.
You can also complete many of these steps using the File Manager from some web host cPanel accounts, but once you take a few minutes to learn it, FTP tends to be faster and more efficient.
Where to Get FileZilla
It is VERY important to get FileZilla from either the official site located at https://filezilla-project.org/, or from SourceForge. I recommend grabbing a copy from the official site.
As with much freely distributed software, there is a lot of malware distributed through Filezilla on other free sites. People take the free software, load malware into it, and then distribute it on their website. A person looking for the specific software thinks it’s safe, downloads it, and infects their computer.
Please note that this is not only a FileZilla issue. It affects almost all freely distributed software, so always make sure you are downloading from a reputable source.
Configuring an FTP Account on Your Web Host
Before you can configure FileZilla, you need to have an FTP account to connect it to. This is created in the control panel of your web host.
- From the cPanel of your web host, scroll down to where it says files.
- Click on FTP.Enter a name for your FTP account.
- Enter a password for the account, or auto Generate a password and use this. Note that if you use the Generate password feature, make sure you copy this and paste it to a secure location so you’ll be able to login later.
- Select the directory that the FTP account will have access to. If you are creating an account so that a contractor can upload files for you, then you should probably limit them to a directory with their name. If you need to make changes to your website, as shown in the How to Create a Child Theme article, then you will need to grant access to the top-level directory. For many installations, this is public_html.
- Click on the Create Button, and you have successfully created an FTP account.
How to Use FileZilla
Launch the FileZilla program on your computer.
FileZilla provides the ability to copy files across the Internet from your webhost to your computer, with an interface that looks like the file manager in Windows or in Mac. The directory and file listing on the left side are the files on your computer and those on the right side are those on your webhost.
To connect to your webhost, you can enter your host username and password at the top of the FileZilla 
window, or you can use the Site Manager which you me to configure your login so that you can launch it by clicking on the name in Site Manager instead of having to manually enter the information each time.
In the Site Manager, enter your FTP host. It’ll be probably FTP.whateveryourdomainis.com. If you’re using a firewall you may actually need to be using an IP address here because if you’re using certain types of firewalls they actually have the site displayed at a different IP address than where the files are actually held so you should get back from your web host. This is true if you are using the Sucuri firewall, which I recommend. In this case, you should be able to see the IP address within your Sucuri installation or in your host’s cPanel.
Select the type of protocol you are using. This should either be FTP, or if your host provides it SFTP. Use SFTP, if possible, because it’s more secure. I use the due default encryption for this.
Note that for any of this, your webhost may have other specific instructions that you should follow.
Select normal for your login type. Don’t accept anonymous FTP because it’s not secure.
Enter the username and password.
Click on Connect
Once connected, navigate to the directory you want to change files in on each server.
I navigated to my podcastaday directory on my computer and to podcastaday.com/wp-content/themes on the webhost.
To copy the directory, I dragged it from the right area to the left area. Note that the progress displays at the top as the files are copied.
Once the files have been copied over, I can login to my WordPress installation on Podcastaday.com and change the theme to the Divi Child which then displays the footer that I changed.
For our case, I demonstrated implementing the child theme I created in the How to Create a Child Theme post.
Common Uses for FTP
When you try to upload a file (theme, plugin etc…), and your webhost says the file is too large. You can login using FTP and copy it.
Troubleshooting If you’ve ever upgraded your site or added a plugin only to be rewarded with the White Screen of Death, or other issue, it’s very frequently caused by a problem with a plugin. In this case, I follow a two-step troubleshooting process. First, FTP to your site and go to yourdirectory.com/wp-content. Rename the whole plugins directory and you do that by your right-click your mouse right click and click on renamed and then you can rename the directory that will disable all of your plug-ins. Return to your website and refresh the page. Is it working? Note that obviously any items that are dependent on plugins, like social media icons or sliders will not appear, but the base site should appear. If it still isn’t working, then the problem is something else, possibly theme related. Try switching back to a WordPress default theme like 2015 and see if it works.
If the site appears after this fix, then you know that the issue is being caused by a plugin. Now for the second more tedious part. Rename the directory back to plugins and then you have to rename each individual plugin to find the culprit, or sometimes multiple culprits. My process is to initially rename all of them and then turn each one on individually and test the site.When you find the one that causes the issue, turn it off and then continue to follow the process. Don’t assume that it’s just one plugin. Sometimes its more than one.
Once you have all of your plugins tested, you can keep the site live while you search for a fix for the one causing the problem. Sometimes, it isn’t needed any longer and you can delete it completely. If the fuctionality is still needed, first see if there is an update available to the plugin that fixes the issue. Also, reach out to the plugin developer to let him or her know. If there is not an update or fix, you may have to search for another plugin that does the same thing.
Another common use for FTP is if you need to edit the wpconfig.php or .htaccess files. Please note that this is an intermediate to advanced topic and a misstep can bring your site crashing down, so follow the directions closely – particularly making sure you have a backup of the original files.
I highly recommend that you don’t make changes to the file that’s the live one. In many cases, for example a broken .htaccess file will definitely break your site. I like to copy the file down from the web server to my computer. You can then edit the file from a text editor on your computer. When you edit a file outside of FileZilla, you need to click on the back and forth arrow image on the toolbar to refresh the directories and 
access the edited file.
Once you have edited the file on your computer, rename the file on the webhost (for example .htaccess-orig), then copy the edited file to the web host and test. If the site works, you’re good to go. If it breaks, delete the uploaded file. Rename the orig file back to it’s original name and go back to the drawing board with your edits.
This should get you started understanding and using FTP with the FileZilla FTP client. As your skills grow with WordPress, you may find other uses for FTP that will help you build and maintain websites.
