Greetings forum - hope you can offer some thoughts

Took my family (2 adults, 2 kids) on international trip to see my parents. I am planning another trip and hoping to use miles, only myself had M&S account, what is the proper way to record miles on my account?
i.e. for my spouse - should I create a separate account for her, request credit (using e-ticket numbers for flights taken) and then transfer it from her account to mine?
what about minor children (who each had their own seat) - what is the proper procedure, create an account for them?

or should I be looking at something completely different and looking into 'family account conversion' or something similar?

Thank you in advance