Let’s get right to it. Here’s how to edit the author of your post on your WordPress website.
Screen options
You can start by clicking on the Screen Options button that is located at the top right.

Author
Once the next screen loads, locate the box next to Author.

After you have located the box, you should be in position to see a new Author box that appears just below the WordPress Editor box.
The location of the Author box may vary in location depending on the plugin you are using. However, it will be located somewhere below the normal WordPress text editor.
You need to select a new author using the drop-down so that you can change the author of the post.
Update
Remember to click Update button to save the changes. The author will be the one that you selected from the drop-down. That is how you change the author in a post.
Note that the drop-down will only give a list of accounts that have been assigned the role of an author.
In case the account you want to assign authorship to is not available in the drop-down, most likely it has not been assigned the role of an author.
Users
If you want to change the role, go to Users and select All Users to see each of the user’s role.

Role
Also, if you wish to edit the user’s role, click the Edit button that appears to be hovering above the Username. Select a new role from the Role drop-down menu and remember to click the Update User button.

After you have updated the user role to the Author, then the account should appear in the drop down.
And that’s it. You now know how to change the author in WordPress.