I need php customisation

I have a code canyon script- Stock Manager advance. This is a small task. I just need 2 minor modifications on the script. Basically one is to add MSG91 or any other sms gateway api to send sms(invoice) along with email which is already there. Another one is to customise the categories which I will tell you on pm. Whoever gives least rate will get it. Wont take more than few hours for sure.
http://api.msg91.com/apidoc/