Which one is the development platform of your e-Commerce webstore?

There is no automation tool that can add meta tags (Title and description) in webpages. First write quality title and description tags for all product pages/webpages in any doc file.

Yes i can understand your problem,but no other way for this.you can use seo yoast plugin for this.But its done by manually.Simple steps for this.

First you can do priority pages title and description .then after low priority pages on regular basis.

Actually you DON'T want to automate this. Duplicate meta tags are not good for SEO. You would be better off leaving Google to chose them than repeating the same all over your website.

This is SEO, mate, hard work, deep research... Make sure both your title and your description have the right keywords! (the first one for rankings, the 2nd to improve CTR).

There's no shortcut to add meta tags. You can't automate this however it can be semi-automatic through this way:

You can do this by database. Ask your developer to add three new columns in database for title, description & keywords. You can put any common word & then call product/category name through variable. This way, you'll get all unique & page specific meta tags.

How many pages containing your site, while it is the best way to use manually ..

There may be one out there, but I have not found an app that will automate the process. I always add the meta tags as I'm building a page. If I'm building a WP site, I'll use the SEO by Yoast plugin. It may be time consuming, but well worth the effort to add them manually if that's you only option.