Sometimes we have a dot after a note. It looks like full stop (see photo below).
it makes the note longer and specifically half of that note’s value, is added to it.
example would be a dotted half note - regularly, without the dot, it gets 2 counts (beats), but with the dot - 3 (2 for its value + 1 which 1/2 of 2, for the dot)
another example would be a dotted whole note = 6 counts (cuz a whole note is 4 and then half of that is 2, so 6 in total)
one more example - dotted quarter note equals 1 and 1/2 beats or 3 eight notes.