Where to put an H1 tag and how many do we need per page?
The H1 tag is supposed to be the most important title of a web page.
When you read a newspaper, you'll agree that generally, each article only has one mail title.
This main title is not the name of the newspaper but a title that has been adapted to the topic of the article.
It must be the same for a web page: only one H1 tag and different content for each page.
Apparently, many integration trainers (transformation of a graphic charter in image format into HTML code) recommend framing the logo of websites with an H1 tag.
Regarding SEO, it is, as you now got it,a non-optimal method.
Instead, it is better that you frame the title of your articles, the labels of the products or the name of the category on a listing page with a nice H1 tag.
As for the name of your website, keep the H1 tag only for your homepage and add, if possible, some keywords you target.
Please note that HTML5 gives us the opportunity to use numerous H1 tags but in SEO, it is wiser to go with one only.