I'd also suggest LinkedIn Learning in addition to what others have provided - https://www.linkedin.com/learning/
Full disclosure, that is my employer :-)
Best of luck to you!
++ https://www.tutorialspoint.com/index.htm some paid
https://www.tutorialspoint.com/python/index.htm - free stuff for slef learning
++ Even youtube has very good video tutorial post.
It may be too simple for you, but is an excellent introduction!
Also, this may sound odd - but YouTube has a ton of great tutorials, so if you are a visual learner, you might start there and then go to W3 Schools to put what you learned into action in a test environment.
The new online platforms besides the above available are:
1.Upgrad 2.QuickStart, 3.Simplilearn
Since you have generically mentioned about IT skills, there are many platforms available online. I assume here in you want to know in regards to computer science on whole. I would suggest you to search the topics you are interested on Udemy, Coursera. Try to go with the free once first and evaluate for yourself how much they are helping you. You can even search the topics your are interested to learn about on YouTube.
Hope this helps, wish you success.
There are multiple platforms available to acquire IT Skills Online. Some of the websites listed as follows:
For video training:-
INE(mainy for networking)
For videos and books
O REILLY (Safari Books Online)
It really depends on what you are after/strengths/ what areas are of interest you. In tech you start with coding, business analysis, database programming, cloud architecture, project management or business relationship management. Tech today requires you to collaborate not just with your peers but across different functions of the business.
Take a look at https://www.coursera.com - they offer a variety of courses including one from John Hopkins on Data Science. Some of their courses come with certification (for a fee).
Let me know if you've any further questions.
Also look into learning about accessible design - being able to build accessible web sites and apps will set you far apart from other candidates.