Your print zine (made by hand on paper) can be self-published by making multiple photocopies. You can print as many copies as you'd like! This is the original, "old school," analogue way of zine publishing. This is also the quicket way to self-publish your print zine. NOTE: the page number order and front and back orientation can be a bit tricky. Get in touch if you'd like help! I can't provide an example here because I am talking about a print booklet IRL!
You can also digitize your print zine and then self-publish it online.
(1) There are sophisticated software programs such as issuu that enable you to digitize your zine while at the same time preserving the booklet physicality of the original zine. Here is an example.
(2) Another method is to "move" your zine into a more low-fi software such as Word or Google Docs.
The first step would be scanning the zine pages or photographing them. Then add the scans or photos in two columns in Word or Google Docs, in order from left to right and top to bottom. This allows you to put the pages in order for reading online. Save as a PDF so people can open without Word. Here's an example. In this example, the front and back cover are just one column, for emphasis. The interior of the zine, or "spreads" are two columns.