Is busking in Taiwan on working holiday visa legal ?

And as a does every city require you to habe permit or only bigger ones?

There are several threads on this site discussing busking. One does need to get a permit and it is not always as easy.
But with working holiday one has an open work permit, so you could do busking.

I think s/he means a busking permit specifically, not a work permit

I busk twice a month but I have ID. The good busking locations are very hard to get. You can get lucky every now and then. It’s a good way to get over performance anxiety and pressure yourself to practice. I have the license . Many places do not allow speakers . It’s pretty boring most of the time . It’s not like busking in the 1980s where you could make a small fortune singing Country Roads .
Hip hop dancers could do well in Ximen. Drummers can do well but most locations now disallow drumming or jazz drums.

I was talking about the permit for busking in my first sentence.

I mentioned the work permit since he asked about the legality. For instance one with only a work ARC can’t do busking.