The best SEO friendly page description must tells vividly about the title and must be not more than 160 characters including empty spaces.
Best SEO Title example
Unlimited Web Hosting Plan: A Shared Hosting Priced TZS. 10,000/ Year.
-The title is 70 characters including empty spaces
Best SEO Description
Our unlimited web hosting plan includes unlimited disk space, unlimited bandwidth, unlimited emails, unlimited databases and much more. All at TZS. 10,000/year.
-The description is 160 characters including empty spaces
product or service title which is around twenty words (20) and not more than 160 characters.
Product or service long description or details that tell about the title above
The whole content of the product or service with any amount of words but advised not too long. About 200 words can satisfy the details of the product or services unless otherwise you attach the product manual to the website or break it to several pages.