There are several ways to decorate your photos. As a rule, such functions are provided by simple image viewers, online generators, graphic editors.
The easiest way to decorate a photo is with a regular image viewer. For these purposes, for example, IrfanView is suitable. It is advisable to download the latest version of the program. Since the newer the version, the more effects are available for working with images. Undoubtedly, there are not too many effects, but for an ordinary user who does not want to radically apply something to a photo, but rather slightly modify it, it is quite suitable.
Online generators are also suitable for simple photo decoration. In order to change your photo (or add an effect), you just need to upload your photo to the online generator site and get the changed image. There are a lot of similar sites on the Internet (for example, https://www.ru.picjoke.com). With the help of any search engine, you can find almost any effect to the user's taste
For a more professional photo processing, you need to install the graphics editor Adobe Photoshop. The editor has a variety of fonts, styles, themes, etc. Those. in fact, any user can, without any special skills, decorate the image as he wants, without using a "standard template". If in your opinion there are not enough add-ons in the standard version of the program, then you can always go to the site dedicated to this program and download the add-ons to your taste. Also, for a novice user, it is recommended that you familiarize yourself with the lessons of working in Photoshop (for example, https://photoshop.demiart.ru/). In a short time, even a beginner will learn many of the tricks of the program and will be able to edit (decorate) photos in an original way.