As you spend time visiting other blogs, you'll probably notice dontation buttons on many blogs. Some may be obvious & say "Donate" while others could be a simple linked line of text that says, "Buy me a cup of coffee".
While the words & appearance may vary, the purpose is the same. In each case, the blogger is asking people who read & enjoy the blog to donate some money to help keep the blog going.
You can easily set up a donation button through PayPal. Just sign up for a PayPal account & follow the simple instructions on the PayPal Donations web pages to obtain the code that will link to your PayPal account. Next, you'll simply copy & paste the code into your blog (most people do this in an easy way by putting it on the blog's sidebar so it appears on as many pages as possible).
Once the code is inserted in your blog, the donation button will appear automatically. When a reader clicks on the donation button on your blog, they'll be taken to your personal PayPal donation page. Whatever money they donate, will be deposited directly into the bank account you chose during your set up process through PayPal.
It's important to understand that a donation button is not likely to bring much revenue, but it's simple enough to add to your blog that it's worth the few minutes of effort it takes to get it up & running.