Alternative operation of numerical and alpha numerical keyboard

I am testing one MOBILE application ( mobile testing)
I want to send alphanumeric text ( number+letters), Text is 15 numbered GSTIN number whoes first 2 digits are numbers, next 5 digits are letters then 3 digits are numbers and so on, I am not able to send whole 15 digits at a time as application is developed so that respective keyboard opens for that type of digits ( numerical keyboard for numbers and alphanumeric for letters).

Please help.

Sanket Gharat.

any one have any idea about this,
please help…

@kazurayam any idea about this, please help ASAP.