Generally speaking, there are two kinds of files in PDF format. One is a scanned version. Such files are all made in the form of pictures and cannot be directly converted into WORD mode. They can only be cut into pages of pictures first, and then recognized by word recognition software. Another file that converts a WORD document into a PDF by other tools can be restored by converting the PDF into a WORD tool. Of course, the recovery effect may be different.

Character recognition software generally has a good recognition of Chinese characters, pinyin and numbers, but if special characters or articles in mixed languages are added, the recognition effect will be lower. The recognition effect of professional symbols such as staff, notation and staff is basically not good.