As you seem to intend using the PDF format, there is no built-in possibility to avoid sharing. The most complex manner to secure your document is to apply an open password to the file. But if that password is not individualized, it is a very very weak protection.
If the password is individualized, you really need some good software to handle that and the protection is mostly weak as anybody with the password will be able to open the and read the file.
The only real option is not a cheap one, as you will need to introduce your reader with built in DRM. You see how difficult it is to keep all those films and audio away from being copied. It's love's effort in vain.
Best is to buy you into an existing distribution solution.
Regards, Abambo Hard- and Software Engineer and Photographer.