slight tangent from my ramblings in the other thread about depression and motivation to not let everything fall apart, you gotta feel it out on a case by case basis, but I've found the best way to help a person with anxiety is to be socially present but not do stuff for them, while the best way to help someone with depression is to give them space but do as much of the work for them as you can - ie, don't just say "your favorite band is in town" link the site selling tickets in your DM
additionally, speaking from my own experience with depression, in a depressive episode im much more likely to respond to friends asking if i want to do dinner if they say "do you want to get dinner at [restaurant]?" rather than "do you want to grab dinner?" because at that point no manner of cuisine seems appealing so just pick one for me i do not care
It's generally not a great idea to do stuff for a person with anxiety because then they're gonna worry if you'll be offended if they don't end up making use of whatever you did or if it means you think they can't handle life or if they'll be beholden to you. With depression not comorbid with anxiety they doooo noooot careee

Also important to note, do not do nice things for someone with depression expecting reciprocity, the reason to do nice things for someone with depression is that they are your friend and their happiness pleases you

actually that applies to everyone, it's just more bluntly apparent with people in a major depressive episode

A great way to help a friend with anxiety is to listen to them and give them a safe space to vent without feeling like they are being frivolous or overreacting. A great way to help a friend with depression is to regularly send them memes or videos or other dumb things they might like even though they don't respond so that they don't feel like they've starved all their friendships and are forgotten by the world and have nowhere to turn once they actually do feel like talking
those friends who have sent me dumb bullshit every now and then even when i don't respond for weeks have honestly been a real lifeline - in the lowest part of a depressive episode you don't realize you're drowning, and if you start to improve enough to become cognizant of how bad things are, you're desperate for anything you can grab onto to keep from sinking back to the depths. This, not the absolute lowest point, is actually the most dangerous part of the depressive cycle
@Xibanya I gotta remember that. And send friends more stuff.