https://www.sudokuwiki.org/sudokux.aspx is a useful site. I'm personally a fan of the killer variety.

Its solver is interesting in showing the individual steps.

For the same puzzle, https://www.sudokuwiki.org/sudokux.aspx?bd=06039000804900150...

if you like sudoku, you owe it to yourself to check out the "cracking the cryptic" youtube channel and get introduced to the delightful world of variant sudoku.