[millhouse1112]

What app?

[aardvark179]

Just the normal iOS notes app.

[therealdrag0]

For checklists, iOS Reminders app is great,

[loloquwowndueo]

But you can’t share it with people running Android.

[8n4vidtmkvmk]

Microsoft Todo, formerly Wunderlist, may or may not have an iOS app. It's pretty good.

[loloquwowndueo]

Todoist exists but both require a more complicated setup.

It’s been established the main point of the posted app is having shared lists with no install or account creation required, just share a link.

[volteret4]

Tasks or Markor are what I use and both are great, and you can syn both pretty easily on different platforms.

[jasfi]

Not op, but ColorNote is good.

[jasonm23]

Text.