Yes, it is possible to lock a PDF file without affecting its quality if the right tool is used. In my case, while working with a few office documents, maintaining formatting was very important. Having attempted a real solution, the document was secured using a password as well as very powerful encryption without changing its original format. The font styles, pictures, and other aspects maintained their original formats even after securing. This could have been facilitated by software such as the Softaken PDF Protector Tool, which offered password protection among other aspects. This way, the document stayed secure without losing its professional appearance. It worked well for both personal and work-related PDF files.
Visit here: https://www.softaken.com/pdf-protector
Visit here: https://www.softaken.com/pdf-protector