How many times have you forgotten an appointment, a birthday or anniversary Or you remembered too late to get flowers or a gift?
There is a real need for someone who will keep track of all those dates, times and places, and get a call to remind them. You can do that - all it takes is a daily planner and a telephone. You can even send an email follow-up.
I know one enterprising person who took it a step further. You can pay him to send loved ones (or even enemies) letters, Christmas or birthday cards etc. - AFTER YOU HAVE PASSED ON! In this case, the client brings you the cards or letters, already signed by the client. He arranges in his will to have the executor notify you when he passes. You then send his cards and letters according to instructions he gave when he signed them.
On the envelope he has a rubber stamp that simply says, "A note from Heaven".
As an invisible secretary, you can also offer other services, such as typing transcripts.
Put on your thinking cap - no matter your circumstances, you CAN be self sufficient.