I keep finding that Todoist is missing from the iOS share sheet and I can’t find a way to get it back on. Is anyone else having this problem?
Googling the issue it appears that this has been an ongoing problem which seems to fix itself and then arises again. Any thoughts appreciated, it is a function I use a lot.
I have the same with Tweetbot. It comes and goes. Research when I first noted it showed that this is a common problem for numerous apps. No-one seems to know why.
At one point recently around half of what was normally in the iOS share sheet was missing for me (including Drafts and Spark, the two I’d wanted to use). Restarting fixed the problem for me. It sounds like I shouldn’t expect that to last.
Thanks for your reply. Have done another re-boot and the Todoist share is back. Not sure how long it will last as it seems this is an ongoing problem affecting a number of apps.
I keep finding apps disappearing from the iOS share sheet—sometimes DEVONthink, sometimes Facebook, etc. no pattern. Restarting the phone always fixes it, but it is a pain.
What’s missing in iOS is the equivalent of “Open With…” from macOS. If an app doesn’t want to receive the text or image or URL sent to it, then it can respond with “whoa, not mine…”.
(Something could be ginned up for this using Shortcuts – someone might have already done that.)
Yes, good ideal! 
I have this with Omnifocus all the time
1st time sharesheet; not there
Close and tap 2nd time: there it is!
Has been there ever since iOS14 first public beta
(In iOS 15 beta this is even happening in spotlight 
)
Did you try restarting your iDevice?
I had that problem with Things 3 and that is what I did which resolved it.