Decent poker apps on Windows 10?

My dad wants to be able to play poker on his new computer. Unfortunately, most every program for playing poker is full of spam and malware. Do you have any suggestions for programs (or websites) that aren't terrible?

He mostly wants Texas hold'em but if it's a combo kind of situation that has lots of different styles, so much the better.

EDIT TO ADD: Probably everyone will be happier if it is free and not playing for real money.

Thank you!