This is pure choice.
It is not a legal obligation to have readings in your Ceremony.
Most couples like to have readings,to involve someone they didn’t have as part of the wedding party.
If you choose Readings, I would suggest a maximum of 2, as you want to keep your family and friends engaged.
I always spread the readings throughout the Ceremony, for the reasons just mentioned.
They can be religious, spiritual or even “slightly” humorous, (save the jokes for the Reception) I have many samples of readings, and so does Google.