One can visit or get legal opinion from lawyer, you can create on yourself, copy and past one from another site (Not recommended as you might be breaking copyright), or use one of the many sites which offer to create free policies etc for you.
These generated policies, terms, disclaimers etc can be used as is, you can modify them to make them more suitable for your region/country, or you can take those to your lawyer to fine tune them. For most small websites, the generated privacy policies etc will in most cases be all you need.
If you’re running a large website or e-commerce site it might be wise to scrutinize them and adapt them to your specific needs. Also be aware countries/regions might have different laws.