Thanks for your consideration!
In the game itself, you can find clickable links that will direct you for options to donate. There is a Paypal link for a 1 time, and Subscribestar for monthly. I try to offer fun things on Subscribestar like teaser images, and between updates I will put up a poll that will decide what gets worked on next.
You can find these by clicking on the button Main Menu -> Support the dev and social