Move a WP site to anoth domain

Hi all

I have been developing a site here – https://www.markstestingsite.co.uk/wrag and will need to move it to https://www.wrag.co.uk shortly.

What is the easiest way to get the content from my testing site to the other site?

At the moment im planning on manually copying and pasting stuff from one to the other but im sure there must be a quicker and easier way of doing this so its exactly the same. Possibly something to do with the databases or something??

Thanks for your help.

Mark