Display Campaigns: Keyword-based and Placement-based campaigns targeting the Display Network. The {placement} parameter is populated when the ad is shown on a content website.
Video Campaigns: The parameter is available for ads that appear on YouTube or partner sites where placements can be identified.
Shopping Campaigns: The {placement} parameter is supported for shopping ads when placement data is applicable.
Hotel Campaigns: The parameter is available as specified in the dedicated help section for hotel campaigns.
Performance Max (PMAX) Campaigns: When using PMAX campaigns, the {placement} parameter is passed for clicks originating from display placements.
According to the current Google Ads documentation, Performance Max campaigns do support the {placement} parameter when a tracking template is used. However, note that if you’re relying solely on final URL tracking without a tracking template, the {placement} parameter might not be populated. This means that for PMAX campaigns configured with a tracking template, you should receive placement information, whereas with final URL tracking, you may not see this parameter.
Demand Gen Campaigns: The parameter is supported for these campaigns, ensuring placement information is transmitted if applicable.
Search Campaigns: For pure Search campaigns that do not extend to the Display Network, the {placement} parameter will not be populated.

