Welcome!
I'm assuming you play electric guitar with light/medium gauge strings.
I would start on the G string at the 12th fret (string tension here is easier to deal with), with the aim of bending up to the A note heard at the 14th fret.
1) Fret the A note at the 14th fret and play it a few times listening
carefully to the pitch. Sing it out loud, keep that pitch in your head!
2) Now, fret the G note at the 12 fret with your ring finger and
supported by your index and middle finger,
push the string up till you get to the A note. When you think you've got it, keep playing the bent note, and sing it out loud!. Then release the bend and check against the 14th fret A note to see how close you got. This will probably take a lot of practice. When you're comfortable, move on to other strings and fretboard locations. Be careful not to hurt yourself!..it's easily done, so take your time and warm up by shaking your hands out and by playing what you normally play for at least 10 minutes before trying this type of focussed exercise.
I'm sure that others will chip in, but I did it by learning guitar solo's I liked note for note and then trying exercises as described above to improve my accuracy. Learning solo's note for note also taught me about the different types of vibrato that players typically add to bent notes.