Automatic email notification for 1 year of Birthday

Yes it is doable - You have several options.
you could in theory create a formula or other date filed to add 365 days to the stat date and have this show on a daybook view with the email field. if you only a a few records to do each year then you could manually go in and process the email send (on the email field) and send a designed template within Ninox or fire up your email client (ie outlook) and select a pre designed template there. Or if you want to go more complex you cab use a button to fire of an email via smtp (again you can design your letter etc within ninox)

you can do this one account at a time or even have it run down the accounts to fire say 100 off a time.

As said all doable but there are several approaches you can take.

a lot depends on the d=sort of volume you what to deal will

I use all the above methods

example: when I open a new customer card. I have a date tracker and fire off (from a button to my email client) a nice welcome letter. Then it sets the date to say 1 week and moves that client further down the chase/reminder list) next time I fire the button I send a mailer to that client  and my tracker redates and updates the audit file to emailed status 2 showing Welcome letter / Mail 1 (branded clothing etc).

I chose this to b manual activated because I want to pay particular attention to the account and take the opportunity to llok at an orders view on the same screen layout..

converserly I send out month;y updated ie updated price list (as an attachedment) that if fired off globally to all subscribed accounts

Hope that gives you some insight - there is some basic and complex videos on you tube and on this sight - sdee below as these you get you started

https://ninox.com/en-tutorials/how-to-create-email-templates

https://www.youtube.com/watch?v=6qIPzG0uJJM.

Otherwise think about what/how you want to approach it and we will of course help guide you

Mel