With some stuff- at least down here- you really do need to get HOA approval first because the contractors won’t start the job without clearance. That was the case with our fence replacement.
Unfortunately for us in that case, the combination of getting that clearance and being good neighbors by pushing the job back a month. They had a visitor from the UK who was staying for 3-4 weeks, and we didn’t want to sour that with the noise of a work crew. But unbeknownst to us, that changed starting time meant that the city’s new building code for fences had changed. The contractor had to get new permits and actually alter the construction plan & techniques.