Questions About my Citizenship application

[coucou12]

Hello
I applied for naturalisation for British citizen 3 months ago through online application with help of NCS
I never received any acknowledge letter
Only the receipt of the money when I paid online same day I submitted my application form

Now 3 months later I have received a mail from the home office containing my evidence documents that I have submitted with my application form and with those documents a letter from the home office saying that they are returning my evidence documents and my application was successful and I should wait for the ceremony letter to call my local council to book a date

Now my question is

Is it this letter what they call the approval letter or I need to wait to receive an approval letter and the ceremony letter?

I know I sound a bit silly but I really want to know and if it was the case why wouldn’t they send it all the same time as I have provided the home office with next day paid returning mail with my address on it signed for with tracking number

Please any suggestion is welcomed as I would love to know

regards
sam

[CR001]

Not sure what you have not received or if you have received your documents in the prepaid envelope you sent.

It is an approval letter you got.

Ceremony letter is sent separately.