Moved from One server to Another but old Links Redirection

Hey Champs,

i have succesfully moved from site from https://www.imsciences.net/ fun to https://www.hamarafun.com with all the old stuff
IT ALL WORKING PERFECT
but
i dont know how to redirect my site to new address so i put in index.php file

<?php
header( 'Location: https://www.hamarafun.com') ;

?>

and it did the magic by redirecting all the traffic of “/fun” to new address

all i want is it posibble if someone at old address click a category and it open in new site with new address but same category

there is something for joomla i used in past but in wordpress can you help please?