Q.red flowering geraniums for wedding
My daughter is getting married on July 18th and wants red flowering geraniums (Pelargoniums) as decorations. I have taken cuttings and am growing them in pots. How do I ensure they have fresh blooms on the day? When should I pinch or cut out old flowers to get the best show?

These are plants you have started from cuttings?
It may be quite difficult to get your plants to bloom on your exact date!
Proper conditions; light, watering, and deadheading spent blossoms will help your plants grow and look their best.
Have lots of plants so you can select the best ones for your day.
Here is a couple links to care.
https://www.gardeningknowhow.com/ornamental/flowers/geranium/geranium-care.htm
https://www.gardeningknowhow.com/ornamental/flowers/geranium/pruning-geraniums.htm