I need help to process my thoughts into correct English.

Hi everyone,

I have been know as the name David to my friends, I applied for some stuff that I used my legal name e.g. Jainokiv Zub (the name that matches my ID card), how am I going to tell the other party that David is my nickname?

I mean I was told to email another department after I submitted my online application to tell them that I have submitted the application so they can process it, in the email I also wish to inform them that David is no on the application form, I want to say something like:

"Hi, I have sent the application. Please process it. The name of the application is Jainokiv Zub (my legal name). David is my nickname. Best regards, David"

"Hi, I have sent the application. Please process it. The name of the application is Jainokiv Zub. David is my nickname. Best regards, David"

"Hi, I have sent the application. Please process it. The name of the application is Jainokiv Zub. Best regards, David"

I mean I do not want them to think why is David Zub emailing them about Jainokiv Zub and think that they are different person.

I am not sure if what I have written is correct.

Could someone please help me to write what I wanted to say in better correct English?

I greatly appreciate your help. Thanks a lot.