My e mail address is *******.******@btinternet.com. I am continually being asked to enter password four Dickmorris.com. This does NOT exist. How can I cancel this from my machine
It's probably your browser which will be holding that information but you've not told us which browser you're using. If it's Safari, this might help:
https://support.apple.com/en-gb/guide/safari/passwords-sfri40599/mac
(See also the 'Autofill' link at the foot of that page)