Welcome, Ashraf Emam! It would be helpful if you would go to the
Introduction Forum and tell us a little about yourself, especially your level of experience in soap making.
That being said, I make lye-based liquid soap, body wash, foaming hand soap, and shampoo. It is best to add fragrance to
finished LS warmed to
140°F (60°C). Stir gently to mix in. It's best to first test the fragrance in a portion of LS, rather than the whole batch, to see how it behaves. Depending on the fragrance, some may thin the LS, some may thicken it. Most often, it does neither and can be added at room temperature.
Polysorbate 20 or 80, used at a ratio of 1 part fragrance to 3-4 parts fragrance works well to make the FO/EO water soluble and easy to incorporate into the batch, but it is rarely necessary.
For scenting liquid soap, I use
MMS Fragrance Calculator
I also like
WSP Fragrance Calculator
For scenting with fragrance oils, I've found that the amount to add is the same for all with few exceptions. The amount varies for essential oils. Both calculators follow IFRA guidelines for scenting soap so you can be assured that you are adding the EO at a safe level.
For color, I use the 4 Basic Colors and the Neon Colors of
McCormick's Food Coloring & Egg Dye that I buy at the grocery store. I add a drop at a time to the finished LS at at room temp until it's the shade I want. Some colors do better than others. Once again, test a small portion first. You can also find food coloring charts online that allow you to mix different shades.
NOTE: Some say that food coloring doesn't last, but I've not found that to be true, but then I use up all that I make fairly quickly. I've never tried testing LS color for a year.
HTH (Hope This Helps!) and best of luck!