Generally speaking, an independent claim should include a preface and a postscript. The preface should include the technical features closest to the existing technology, and the postscript should include the necessary technical features that distinguish the existing technology. Of course, the independent claim can also have no preamble. It should be noted that unnecessary technical features must not be written in independent claims, otherwise the scope of protection is too small, and others can easily bypass your patent.
In addition, if it is the first time to apply for a patent, it is not recommended to write your own materials. Patent application materials are very professional, and sometimes a good patent will be worthless if it is not written in place. It is recommended to apply to the local patent agency. After all, in the face of a good patent, the agency fee is small money.
I hope my answer can help you.