Can somebody suggest me a template for provisional patent. I am looking for one in the area of mobile App?
What @EricShain is indicating is that, while provisionals are much more forgiving, filing a non-provisional without engaging an attorney is never recommended.
You want to stay away from "mills" such as LegalZoom, which will likely do more harm than good.
Solo-practitioners are the way to go if budget is an issue. I've gotten quotes as low as $3500, flat rate, not including filing fees, which will be low initially if you are a solo inventor.
The root of the problem is that it's not enough to properly describe the process in the patent. You also need to take into account legal precedents, and that will be reflected not just in the structure of the patent document, but the language used.
I could give you a long list of cases you need to be an expert on to navigate this at a high level for a software patent (Enfish, Bascomb, Alice, etc., but you'll still lack the experience and specialized knowledge of a patent attorney.
I don't know what you situation is with the provisional patent, but it's a low cost way to get a year of "blanket" protection before you have to file the non-provisional. If you never publicly disclose, you can keep refiling provisionals until you have the funds to engage a patent attorney for the non-provisional.
A template for an app patent won't be much help, except as a starting point. The problem is, "the devil is in the details", and this factor weighs very heavily in patent law. Even a slight mis-step in the provisional could irreparably harm the viability of the application.