How to encode to ascii different european languages ​​in php?

Question

ASCII

There is a site in utf8, there are many users from European countries on it, they enter all sorts of different words in their languages, there is software that generates beautiful pictures / postcards with their words.
The software supports only ascii
Here is a table

In which, in general, there are almost all the characters that are found in European alphabets.

Answer 1

Understand what kind of encoding it is (for example, it is similar to 8859-1 ru.wikipedia.org/wiki/ISO_8859-1 or maybe ru.wikipedia.org/wiki/ISO_8859-15 ). Convert to this encoding.