National Covid-19 Immunisation Programme will begin Phase Two starting from 18th April this year. The recipients eligible for Phase Two vaccines include senior citizens and those with high-risk conditions as well as the disabled. If you belong in any of these categories, MySejahtera will ping you an alert informing you that you're up next for your vaccine appointment. 

source: The Star

According to Twitter user @ailyn_ng whose parent has recently been notified, here's exactly how the MySejahtera app will inform you:

My mother received a notification from MySejahtera at about 11pm that she has been selected for the vaccine program. After going into MySejahtera app to resubmit her assessment, the system immediately assigned an appointment for her. Super efficient! Well done @JKJAVMY ! pic.twitter.com/ulZvQFWP04

— Ai Lyn Ng (@ailyn_ng) April 5, 2021

As shown in the screenshot below, important details such as the location, date and time of your vaccine appointment will be disclosed clearly on the app. You will be notified two weeks ahead of your appointment and a phone call or a text message will also be sent as a reminder three days prior. 

source: @ailyn_ng (Twitter)

You will be given the option to either accept or decline the vaccine. If you do accept the vaccine, you will receive a digital vaccination certificate once you've completed both phases of vaccination. It'll look something like this:

...and that's how MySejahtera will inform you of your vaccine appointment. If you haven't registered still, here's your reminder. #KitaJagaKita