There are laws in many states covering voting by electronic means, by email or other online process. Some states say electronic voting must be unanimous in order to carry. Others don’t have any rules about it.
Check with your state agency that regulates nonprofits. You can find out who that is at the IRS web site here.
How to include that information in your bylaws
Include the ruling you found out for your state
If there is no law against it, decide how you will handle electronic voting.
If there a different requirement for the number of electronic votes required to make a decision, include that info in your bylaws.