H4 dependent visa holders are spouse/children of Primary H1b Visa applicants.
They can stay, study and do volunteer jobs in the USA.
They cannot work without work authorization.
a) If the primary applicant has i140 approved, then the H4 applicant can apply for an EAD.
b) If the perm or GC is applied, then the spouse can work.
If they don’t have both of the above, then below are a few of the leisure time options that H4 can do:
1) Upload YouTube videos some recipes/travel/technical etc.
2) Write blogs, content is very much important in the world of the internet.
3) Give appropriate survey comments on legitimate survey websites, like survey junkie, etc.
4) Volunteer for a noble cause and support.
5) Craft and artwork and home decorations.
Hope this suggestion is useful to you! Have a great time