When importing feed items using Feed to Post, you can set the author to be assigned to the imported posts.
You have three options here.
Option 1 – Use Author in Feed
If a feed provides author information, you can choose to use this information for setting the author.
If that author name does not already exist on your site, you can set the plugin to create it automatically or alternatively use the fallback user.
In order to show the author for your posts, WordPress requires that a user must exist on the site. Simply giving a name will not work.
Users are identified on your site by their email address. If the feed does not provide the email address, the plugin will automatically generate one using their name and the domain name of your site. For example: John Smith will receive the email address email@example.com, where yoursite.com will be the domain name of your site.
Created users will also be assigned a randomly generated password.
Option 2 – Use a Particular Author
You can also choose to assign all imported posts to one particular user, which already exists on your site.