This is a lovely dog

I can't tell the breed; considering that your friend just found it, it's probably a mixed breed.

It's possible to train it to bark less, but it takes a lot of patience and time. Basically, you should ignore it when it barks (however hard that may be), and make sure that it is quiet before giving it food or treats. You should also speak to it in a positive tone when it is quiet. This might take a long time (perhaps a month) and you will need to be consistent; if you break the pattern, all the other training is useless.