Yes, they are the same sometimes. ("Sometimes" seems to be a key word in the English language).
When "anywhere" has a positive meaning, they are the same.
Anywhere/Wherever you go, you find people who speak English.
Whatever/Anything you want to do is fine with me.
However/Any way (two words, not one) you say it, it is still a nice thing to hear.
As I write this, I �m beginning to realize that anyone/whoever aren �t the same as the others.
Anyone (not whoever) can learn English if they work at it.
Whoever (not anyone) told you that needs to research it better.
In negative statements and questions, only the "any" words work:
Did you go anywhere last night? No, I didn �t go anywhere.
Are you cooking anything special today? No, I �m not cooking anything special.
I �m sure there are many other situations that I didn �t mention, but these are the basics.
Bruce
