DPI stands for Dots per Inch, which refers to the number of ink droplets a printer will produce per inch while printing an image. Today it is a term often misused, usually to mean PPI, which stands for Pixels Per Inch. When someone says they want a photo that is 300 dpi they really mean that they want 300 ppi.
A digital photo is made up of pixels. PPI is the digital photo's pixels dimensions divided into the paper size to be printed. So, to get a PPI or DPI number for any digital photo you need to know the intended print size.
A request for a 300 ppi (or dpi) image is meaningless in itself - the request has to be accompanied by an intended print size. A meaningful request is for a digital image that will be 300 ppi when printed to 8" x 10" (or any other physical dimension).
What Image Format Should I Save for Printing?
In Fotor Design and Collage tool, you can save your work in high resolution PDF, and this format of image is set as 300 dpi/ppi. High-resolution PDFs ensure good image quality whether printed on small or large paper, but it's important to keep in mind that only text and vector images can be enlarged without loss in clarity, your own uploaded images in the design may still appear unclear when scaled up.
In Fotor Editor, AI Image Generator and other tools, you can only download images in png and/or jpg format, which are usually suitable for 72 dpi. Although the dpi is lower, if you are not printing on a very large paper size, the printed image will still look clear with good quality.
Can I Increase Image Resolution to Increase DPI?
Not really. As mentioned above, the DPI value only makes sense for physical printing, while the clarity of a digital image is determined by the resolution (pixels).
However, if the printer is set to 300 dpi and you want to print an image on a large sheet of paper, the higher the resolution, the better and sharper the image will print. In Fotor, you can use the AI Enlarger to increase image resolution.
* If you want to understand further about DPI, you can refer to this article: The Myth of DPI.