To cut through metal you will need a blade with a TPI between 18 and 24. This may vary with different metals.
To cut through wood you will need a blade with a TPI of between 6 and 20.
Your hacksaw needs to be very tight so it doesn’t bend. When you do a lot of cutting the blade will expand and heat up so be sure to tighten it if it starts to bend.
Hacksaw blades are selected by choosing the correct TPI (Teeth Per Inch) for the type of metal you need to cut. The higher the TPI the more aggressive the cut.
Yes, you can use a hacksaw to cut tree branches. It gives a cleaner cut and you can get to branches in cramped places.
A hacksaw can be used to cut plastic, steel and some other metals.