Date plus one year

Hi I need “ExpireDate” field in the form based on invoice date + 1 year

Expire Date = Invoice date + 1 year ;

suppose we done invoice today (i.e 29/01/2018) then expire date should be 29/01/2019

How will get this ?

You can use nextYr function.
msdn.microsoft.com/…/aa870505.aspx

As mentioned by Kranthi, use it like this:

Date expiryDate;

expiryDate = nextyr(29/01/2018);

Use the return value of type date and use it in field/Column in form Expiry Date