If you bought a Physical bundle, the code for the expansions should be inside the case that contains the Disc.
If your codes are missing then you need to contact the retailer you purchased from.
https://www.bungie.net/en/Help/Article/12131
English
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Hm ok, but there are only 2 codes inside for PS Plus and one for a weapon Pack
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If you've checked all slips inside and the code for the expansions is not there then you need to contact your retailer.