Is this necessary to wash vagina after peeing?

Here are some ...: Unnecessary as long as due topical hygiene is maintained by daily rinsing. Yet, it's a healthy practice to drain and dry the vulva after each voiding. That is all what you need and there is no need for over washing with over use of soaps.

Not a formal washing: But wiping to clear away an residual urine is wise from a general hygiene perspective. In fact, washing particularly with various soaps after urination could lead to irritation of the vulva, the external part of the female genitalia.