There are many ways to learn to read music. You can watch youtube videos, read method books, or hire a teacher to help.
To get started on your own, buy some staff paper at your local music store. The five lines of the staff are where you’ll read notes from. On the bottom of the staff, the space between the bottom line and the one above it is where you’ll put your first note. That is called a “space note” because it is in between the two lines, literally on the space. That lowest note is an F.
The three spaces above F are where you’ll put the remaining space notes. Those notes will be A, C, and E respectively, E being the highest. FACE is a good acronym to use to remember the space notes on the staff from bottom to top.
For line notes, put a note so that it goes right on the bottom line of the staff. That is an E. Each line note above that will be G, B, D, and F. EGBDF (from bottom to top) can be made into several acronyms. The most common ones are “Every Good Boy Deserves Fudge,” “Every Good Bird Does Fly,” and more. Feel free to make up your own!
As you get familiar with these notes on the staff, make flashcards. There are even pre-made flashcards you can buy to help you out. Each card should have a staff on the front with the note on it, and the letter name of the note on the back. Drill these consistently to memorize which note is located in which spot.
After that, practice reading actual pieces, in context. If you play an instrument, practice playing each note as you read it. It’s OKAY to be slow to start. I always tell my students that the slower you practice something, the faster you’ll learn it. Do a little bit each day to break it down into smaller chunks.
Over time, you should become more and more comfortable reading notes on the staff, and then you can move on to the ones below and above it. If your instrument has a fingering chart, this is also a great way to study how to read the notes and associate them with the fingerings on your instrument.