mask domain in url using .htaccess

Heya thanks for any help in advance

So i have 2 domains both with same hosting company namesco called dmfoundation.org.uk and dmtrust.org.uk.

dmfoundation.org.uk(no cpanel is apache http server) has all the files for my wordpress site and dmtrust.org.uk (cpanel) has no files inside it.

what i want to do is redirect dmtrust.org.uk to dmfoundation.org.uk but i want all the urls to appear as dmtrust.org.uk/whatever file name. rather than displaying dmfoundation.org.uk/whatever filename.

any question feel free to ask.

Cheers, Grant