Arabic origin:
* Amira (most common spelling)
* Amiera
* Amirah
* Ameera
* Amireh
Other variations:
* Ameeira
* Amara (meaning "eternal," often confused with Amira)
* Amiree
It's important to note that the pronunciation usually stays consistent even with these variations.
Ultimately, the best spelling is the one you prefer and find most aesthetically pleasing.