Hi @demo1111111111 ,
I do not get your question.
What's your goal of this?
Do you want to prefill the currency field on load of a form?
Do you want do fill in the currency after saving a new record?
In case this is not a mandatory field on creation, you could use entityformmetadata or on CRM side a workflow/plugin which is triggered on create of a new record.
The solution depends on your requirement which is a bit lacking for me. 🙂