FTP data required

There is a way to upgrade the plugins manually using FTP, take a look on that.

Are you asking about how to access your files via FTP?
Ask your webhosting vendor to help you find that information in your account.

FTP data required for installation or updates of plugins and themes

Can you clarify a little more on what you mean? The more information you can provide the better can help. Are you asking if FTP is required to update themes and plugins? That answer is yes and no. Yes, if a host has their file and folder permissions set in a certain way and no if not. More often than not all you would do is click a few buttons and you can be on the latest version of a theme or plugin. The only possible exception would be is if you purchased a theme or plugin and they don’t have the ability to use WordPress update capability.

Does that help at all?

Is your problem that WordPress is requesting FTP credentials whenever you attempt to install/update a plugin or theme? If not, please explain what you mean. If so, please read on.

The issue is that your webserver (Apache/nginx) has an old and outdated configuration. Please contact your hosting company and request that your webserver be updated to “FastCGI” so PHP runs as the filesystem owner. PHP should ideally be something called “PHP-FPM”. This will solve your current problem, and many others you have yet to encounter.

If your hosting company is unilling to make this change, or if you have unmanaged hosting and do not have the knowledge to make this change, then you must provide FTP credentials to WordPress every time you install or update a plugin/theme. Or better yet, find a new host that configures their webservers for use in 2019, not for use in 2009.