It doesn't have a sound of its own, but it slightly modifies the sound of a preceding consonant making it "soft".
In Slavic languages (including Ukrainian) most of the consonant sounds have two types - we call them hard (they are normal consonants, like т, л, п) and soft consonants (ть, ль, пь, so we normally add ь to mark them, but there are also other rules that affect "softness").
The proper term for the "soft consonants" is "palatalized consonants". They sound different to us, and it does sound off if someone says "допоможіт" instead of "допоможіть", but of course we understand that it's very difficult to master the correct pronunciation if you are foreigner and not accustomed to make this distinction.
It's also very difficult to hear the subtle difference before a hard sound and it's soft (palatalized) counterpart for people who are not used to it.
You can read this article:
But if you want to hear the difference, you really must listen to a lot of words with soft and hard consonants, being aware they are different. I can see you've also been learning Russian, they also have this distinction.