As a content creator you are responsible for correctly mentioning a collaboration. This applies not only to collaborations for which you are paid, but also to assignments for which you receive a product.
The Advertising Code Foundation has created its own advertising code for Social Media & Influencer Marketing. Here they explain per channel which ways you can use to clearly mention a collaboration.
Advertising mention in blogs or articles
Via text in a post, such as 'Advertorial', 'This article is in collaboration with [advertiser].' or "I received these products from [advertiser]."
Advertising mention in posts on Instagram, Facebook or Twitter
Via hashtags in or under a message, such as #ad, #adv, #spon, #collab or #partner
Via text in the message, such as 'collaboration with @adverteerder' or 'received from @adverteerder'
Advertising mention in videos on YouTube
Via a voice message in the video, such as 'this video contains a paid partnership with [advertiser]' or 'I received these products from [advertiser]'.
Via text in the description, such as 'This video is in collaboration with [advertiser].'
For more information and examples, view the guidelines of the Social Media & Influencer Marketing Advertising Code.