We've summarising multiple free online learning platforms below.
Alison - https://alison.com/en
BBC Bitesize - https://www.bbc.co.uk/bitesize
Coursera - https://www.coursera.org/
Improving digital skills
Duolingo - https://www.duolingo.com/
FutureLearn - https://www.futurelearn.com/
GCFLearnFree - https://edu.gcfglobal.org/en/
Khan Academy - https://www.khanacademy.org/
OpenLearn - https://www.open.edu/openlearn/
Unionlearn Resource - Value My Skills Online