Hi @kamil91 ,
Which PowerApps License do you have for your account?
Do you have a Office 365 license includes PowerApps for your account?
If your account owns a Office 365 license includes PowerApps, then you could embed a canvas app into your D365 F&O Entity.
More details about Office 365 includes PowerApps, please check the following article:
https://docs.microsoft.com/en-us/power-platform/admin/pricing-billing-skus#powerapps-for-office-365
In addition, you could also consider sign up for a PowerApps Plan 2 free trial license using your Office 365 account, then during the trial, you would have access to all of the features in PowerApps Plan 2.
More details about signing up for PowerApps Plan 2 free trial, please check the following article:
https://docs.microsoft.com/en-us/power-platform/admin/pricing-billing-skus#powerapps-plan-2-free-trial
In addition, as an individual developer in PowerApps, I think the PowerApps Community Plan would be a better choice for you, please check the following article for more details:
https://docs.microsoft.com/en-us/powerapps/maker/dev-community-plan
More detials about Licenses supported in PowerApps, please check the following article:
https://powerapps.microsoft.com/en-us/pricing/
Best regards,