I like to link both ways. Here’s an iOS shortcut that finds a project in OmniFocus based on a fragment of text.
It leaves a link to the project in the paste buffer as a Markdown link. Just paste that into obsidian and you’re done.
https://www.icloud.com/shortcuts/f309971829044833bd99961d0bb64c7d
For example, I typed “obsid” into the shortcut input and it found my Obsidian project. I selected that from the list of matches and it left this in the paste buffer:
OmniFocus: [Obsidian](omnifocus:///task/jeDhaNbUut_)
Addendum: I guess this is only useful if you’re using the iOS beta of obsidian or use 1Writer or IA Writer as an alternative.