Invoices kept in document with user information in no sql database is recommended? I have a application which has tenant details like 

{ 
"name" : "", 
"Address" : "" ,
...
Bills :[
     current : {"rent":"" ,"electricity":"" ,"date":""},
     previous : [{"rent":"" ,"electricity":"" ,"date":""}, 
                {"rent":"","electricity":"" ,"date":""}]
] 
}


I have Bills of a tenant in the tenant document itself , 
is this model recommended / acceptable ? 

The reason would be silly , 
I thought since the scope of bill is only viewing and won't do any computations on bills , So keeping it in a separate document would be a extra work . So I kept in this tenant document itself .

So Keeping bills in this type of document is good or bad ?

If I get some clarity it would be nice , Thanks .
Almost always with databases, it depends on what you're going to do with the data after you're stored it.  

How are you going to retrieve and process it? 

If you only ever access this data by Tenant, then carrying a block of "stuff" around with each Tenant "document" is probably OK.
If you wanted to start querying and comparing bills across your tenants, though, this structure might be inefficient. 


  ... won't do any computations on bills ... 


Do you not have to summarise your rental income for your annual Tax Return? 

That would mean pulling out any Current or Previous "rent" entries that fall within the last Tax Year - I suggest that might get just a bit fiddly with the data structure you have (and, although you've not shown any, the Date formats that you're using).