What requirements should the product page meet so that the crawler can index the information provided?

The product page must be available, return the HTML code, and contain the necessary information about the product offer. To ensure the correct definition, the product page must contain the valid Schema.org Product or Open Graph Product microdata. In order to determine the data type and to process the information about the product offer in the Schema.org Product markup, the offers property of the Offer or AggregateOffer type must be present. Pages that are marked using the Open Graph protocol must contain the "og:type" tag with the "product" value.
Microdata should be used on all product offer destination URLs in order for our crawler to be able to process data correctly. Only one Product item corresponding to the product offer for the URL should be placed on the destination pages.
In the absence of microdata, our crawler tries to automatically detect the data about the product offers using a special algorithm of web pages analysis. However, this may not always ensure that you receive the correct data. We recommend using content microdata by Schema.org to achieve better results.
If your website does not use product markup and is not compatible with advanced extraction algorithms - you can create a feed with a prepared CSV-file.