Learn openings with software

Website would be Chessable.com

Software would be chess opening wizard.

Personally, I use the freeware Lucas Chess (https://lucaschess.pythonanywhere.com/) to explore variations and to play several games over and over (you can pre-set the opening moves you want) so that it sticks in my head - you can also set it so there's say, 15 minutes on your clock and 3 on the engine-of-your-choice's clock if you want to shorten play but give yourself time to think.

You can use the opening explorer at here are chess.com or the similar one at https://www.365chess.com/opening.php to look at the variations you want to play.

Personally, I acquire books (some are legally free online as .pdf files) that explain the moves in the openings I like - like the Move-by-Move book where, for example, Cyrus Lakdawala may explain that, in a certain position of the Caro-Kann, Black plays ...Nd7 instead of ...e6 or ...Nf6 because it stops White from moving his N to e5 - which inhibits blacks development.  Some of these book are very cheap when used or the Kindle edition is purchased at Amazon.

@ MickinMD: That's exactly what I'm looking for. I have downloaded Lucas Chess and it's opening training is really great and best of all...freeware! Thumbs up! Maybe you can recommend me something similar for my Android device to learn and train openings when I'm commuting? :-) Thank you so, so much. Harry