Q.natural fertilizer
I live in India. My house is in Chennai city. I grow Ixora plants. I use cow’s manure as fertilizer. How many times can I add this manure? What can I do to get more flowers?

An application of an acid fertilizer in the spring with a ratio of 4-8-8 is beneficial. Many times a Palm fertilizer is used for Ixora.
You can also add 3 to 4 inches of composted manure in the spring around the base of the plants.
This will help maintain the ph level.
You need to make sure the cow manure is properly composted. If it has to high of Nitrogen levels, this will inhibit flower production.
Here are some links to help you.
https://www.gardeningknowhow.com/ornamental/shrubs/ixora/growing-ixora-shrubs.htm
https://www.gardeningknowhow.com/composting/manures/cow-manure-compost.htm