Repeat items on iPhone

There seem to be no possibilities to repeat an item on iPhone. On Mac OS there are. On the iPhone only a single date appears.

Can anyone suggest a solution?

I must confess that I do not understand your request. Both on the Mac and on the iPhone there are always 2 date fields available (1 for a defer-date and another for due-date). You can then use a switch to specify which date (defer- or due-date) is used for a rhythmic repetition.
I think you need to formulate your question in more detail.

If you are meaning how to show the repeat options for a task, the can be seen/updated in the Inspector (tap the “i” in a circle at the top right of the screen. If you want to be able to see the options when tapping on a task:

I hope that this makes sense and answers your question.