Hi ValiaPilatou,
Thank you for posting your question in this community.
With the built-in feature and templates, Word app doesn’t contain APA 7th edition at this moment. We understand that the citation formation should be updated accordingly since APA 7th edition has been released.
In this scenario, I suggest you can vote the related idea about Add APA 7th Edition and send in-app feedback in Word app by going to File > Feedback with your contact information, which both channels can let the related team be aware of this scenario and improve in the future. Thank you for your understanding.
However, you can try out the suggestion in the thread shared by Charles above to download APA 7th edition .xsl file from third party and place under Microsoft\Bibliography\Style. Based my test, you can select APA7 under Styles panel in Microsoft 365 apps and insert citations in APA 7^th^ edition format.
Best regards,
Dihao