Conversion of partnership firm into llp

See

As far as partnership is concern,There are two options 

1. oral partnership

2.written partnership

It is not compulsory to do the written partnership but it is advisable.

So you can convert the existing partnership into LLP

It means a unregistered firm can also be converted into LLP

See your partnership firm is unregistered so it has no legal existence, so first you should register it.The process for it is very easy than you can convert it into LLP

OK MY Firm is unregistered under partnership act but we have taken Service Tax , TAN and PAN

As we have Service Tax Number, whether our firm will be treated as unregistered or registered