Q.What Flowers I Can Plant for Full Afternoon Sun
What flowers can I plant in full afternoon sun?

Certified GKH Gardening Expert
This article has some suggestions that may help: https://www.gardeningknowhow.com/ornamental/flowers/fgen/full-sun-plants.htm

You need to expand the question. How tall, what color, maintenance, moisture, annual, perennial, edible, fragrant, container, bed, cutting, butterfly/hummingbird attracting, deer resistant, pet safe; all these factors and probably more should be considered before answering.