You are forced to switch to another domain. Migration process is not so fast and that there is a risk of losing files, data, etc.
You want to protect your page when migrating to another domain.This can be done by following steps :-
Step 1: Copying all current site content to the new domain :Don't redirect anything until you have copied your site to your new domain. This can be done using the Duplicator plugin, which allows you to transfer all your URLs to the new domain, this means it will include all the internal links across your pages.
Step 2: Redirection of old to new site :- You need to perform a 301 redirect which will allow both search engine robots and human users to find the correct page on your new site. This requires finding your .htaccess file, which you can do with an FTP program such as Filezilla which gives you access to the server of your WordPress site. You can find the .htaccess file in your site's root folder.