Help with Permalinks

I have been spending ages to get my webiste url to say domainname.co.uk/%postname%/ or domainname.co.uk/%category%/%postname% but nothing works.

The only way I can get them to work it by adding index.php like this domainname.co.uk/index.php/%category%/%postname%.

I have tried all sorts but still can’t get it to work. When I change the permalink to /%category%/%postname% it changes the pages and posts and when you click on the button ‘view page’, it doesn’t exist – even though it is giving me that page link…

Does anyone know what I’m doing wrong?

Please help.

If it helps my website is https://www.samhankin.co.uk.

Thanks ??