I have been sectioned many times as have schizoaffective disorder.
Yes you can have your phone but not the charger. They normally have to be charged in the nurses office. You can have other devices eg laptop or tablet but nothing that needs to be plugged in as cables/plugs aren't allowed.
You can't have anything that could be used to harm yourself or anyone else & thats a rule even if the patient doesn't self harm as another patient could use the item.
So nothing sharp, no plastic bags, nothing that could be a ligature, nothing with alcohol eg mouthwash, no glass, ceramic mugs, cans of drink etc
They will search all property so will remove & store anything.
Some wards have 'no caffeine' policy so no energy drinks & decaf coffee/tea only.
Smoking & vaping are not allowed but there are some vapes that can be prescribed & used on the ward (the one I was in prescribed dinner lady vapes as they can't be used to self harm & don't give out any vapour)
Ward & trust policies do vary alot & there will be a difference between general wards, specialist & PICU (intensive care)
It's frightening at first but honestly the best friends I have ever made were from inpatient admissions.
Wards can vary from having very unstable & acutely unwell patients to having days where patients socialize, order deliveroo, do activities & sports together, watch TV etc.
Headphones/ear buds with no cable or wires are an essential item.
Snacks & drinks in plastic bottles are useful. All wards I've been on have let patients keep some ready meals & chilled items in the kitchen too.
Be warned that stuff goes missing A LOT, don't take in anything expensive or sentimental value, label everything.
Any other specific questions I will try to answer.
Good luck xxx