\Machu Picchu

You aren't allowed to bring poles into the citadel. My understanding is that if you need a cane for walking, you will usually be allowed to bring in something with a rubber tip. (No metal tips are allowed, because they can cause damage.)

Otherwise, if you are trekking the Inca Trail, you can use them but will have to stow them once you reach the Sun Gate.

By the way, you have posted this in the forum for trip reports. This is the appropriate forum for questions involving destinations outside of Europe: https://community.ricksteves.com/travel-forum/beyond-europe

Poles are OK - we were there in December and many in our group had them - but they must have rubber tips. I think they sell the tips if you don't have them, but you'll want to check on that - but better to just have/buy them before you go. Otherwise, up to you on necessity. Paths are all gravel. It can be a lot of climbing on stairs of varying height and width, some with handrails, some not. I'm short, so poles may have been helpful but I did fine without.

Keep in mind that if you pack the telescoping style of pole, they have to be in your checked bag. I have heard that the folding types are OK in carry on, but again, you'll want to check. You can buy poles pretty cheaply at shops everywhere, even at touristy gift shops, so that is an option as well. Have fun! It's an awesome place.