Preview is the PDF and Photos app that comes with the Mac, but most users use it only as an image viewer and don't realize how many features it has. Many of the system-level apps on the Mac provide a great experience, such as Screenshots, Reminders,merge two pdf pages into one page mac and Screen Recording, that fulfill hard needs and work better with the iPhone. While some of these features are not as feature-rich as third-party software, they're also very clean. The most common uses of Preview are to create, merge, and sort PDFs.

For example, if you want to create a voucher for last month's reimbursement, take a picture of all the vouchers and collect them, then select them all in the Finder and right-click to create a PDF, which you can open and sort by dragging up and down. If you want to add a new voucher, simply drag and drop the picture or PDF file from the Finder into the list of thumbnails on the left side of Preview.

In addition to this feature, Preview has many other features, a few of which are briefly described below:

1. Signature: If you need to sign a document, but do not have a printer, simply use "Preview" to open the file you need to sign, click on the signature menu, and then through the touchpad writing or camera to get two ways to generate a signature, and attach it to the document you need to sign.

2. Encryption: If your PDF file involves confidential information, you can click on the export option of "Preview", select the PDF format, then choose the password option and set the required password.

3. Format Conversion: Preview can convert image files to a variety of file types including HEIC, JPEG, JPEG 2000, PDF, PNG and TIFF. Simply select the desired format when exporting. JPEG and JPEG 2000 support quality resizing, PDF supports encryption and filtering options, and Quartz filters include sub-options to reduce file size.

4. Image Processing: Preview allows you to perform simple image processing operations such as resizing, coloring, instant alpha keying, sketching and shapes. These features can satisfy basic image processing needs.