A way to assess if a website uses cookie, there are different tools:
According to GDPR; if personal data is stored or transferred from a website, the website owner needs to collect a consent before collection of this data can happen.
To use this data you need a consent:
"Processing shall be lawful only if and to the extent that at least one of the following applies:
- the data subject has given consent to the processing of his or her personal data for one or more specific purposes"
Art. 6 GDPR - https://gdpr.eu/tag/gdpr/
So if any third party cookies are used for marketing, statistical, advertisement, or functional purposes, a consent is needed before these cookies can be set.
Example of cookies set from Google Analytics, Shopify Analytics and Facebook on a website:
So if a websites uses third party software that collect and use data through cookies, the website need a consent solution.
When the processing has multiple purposes, consent should be given for all of them."
Recital 32 - https://gdpr.eu/tag/gdpr/
The consent solution should ask the user for a consent for all purposes of cookies.