If you want to use your phone as your EasyCard and you’re not a Samsung user (see here if you are), you can use the Easy Wallet app (Google Play) to beep in and out of the MRT and even use YouBikes! Unfortunately, the Apple version of the app doesn’t include this functionality due to the apparently ongoing tension between Apple and the EasyCard corporation about third-party apps using NFC functionality (although there are rumors this will change).

Click on「我的」 as below:

Then you’ll get a screen asking if you want to register for EasyWallet as follows:

Click 立即開通悠遊付 as above, and then you’ll get a page with terms and conditions which you have to state that you’ve read and agreed to:

Next is the signup info, under 身分證字號 (ID number) you’ll see a link in blue labeled 居留證驗證 (ARC validation), which you should click:

After this screen you’ll be asked to select either an ordinary ARC or an APRC (this is because there is no expiry date on an APRC):

The main difference is just that for the normal ARC (一般居留證), you’re asked for the expiry date on your ARC (居留期限) while for the APRC, you’re asked for the 核發日期 (date of approval):

The rest of the form is the same:

ARC No （統一證號）
Your name (姓名)
Date of birth (出生日期)
Nationality (國籍）
ARC Expiry date/approval date (居留期限／核發日期)
The serial number on the back of your ARC (背後序號)
Then you’ll be asked to take a photo of the front (正面) and back (背面) of your ARC.

Then you’ll be asked to confirm your details and to proceed to validate (it will be checked by the National Immigration Agency no less according to the blurb:

After this you’ll get a message telling you that they are reviewing your ID:

After you get verified, go to the 嗶乘車 part of the app as marked below:

You will be asked to enter your pin (a six digit code), then NFC should work to get you in or out of the MRT.

If you want to enable use of YouBike, you can click 需要協助 marked in blue below, and your virtual EasyCard number should be listed:

You can then use the YouBike app to add this as a card.