HMRC cannot give financial planning advice.
If you are sole traders for 21/22 and each of your trunover is less than £1000 for the year before expenses, then this income will not need to be reported.
If you are looking to set up a partnership for later years please see guidance here:
Set up a business partnership
Alternatively you can set up as sole traders, this would be your choice, please see guidance here:
Set up as a sole trader