WP website showing blank page after moving from subdomain to main domain

you need to see below post to move word-press site one server to other

Ref :- WordPress link

some simple steps follow and change site location

you can update your database using following queries

UPDATE wp_options SET option_value = replace(option_value, 'https://www.oldurl', 'https://www.newurl') WHERE option_name="home" OR option_name="siteurl";

UPDATE wp_posts SET guid = replace(guid, 'https://www.oldurl','https://www.newurl');

UPDATE wp_posts SET post_content = replace(post_content, 'https://www.oldurl', 'https://www.newurl');

UPDATE wp_postmeta SET meta_value = replace(meta_value,'https://www.oldurl','https://www.newurl');