As of the end of October 2022, here are the voice call packages offered by Myanmar’s telecom operators — Atom, Ooredoo, and MPT.
For call rate packages, MPT basically offers three types: Shwe Sakar, Swal Thaha, and Shel Pyaw. The rates for each are as follows.

Starting December 13, 2017, all domestic calls outside the Base Tariff have been charged at a 15-second rate. You can read more about the Base Tariff on MPT’s blog post.
MPT’s other voice call packages are as follows.

MPT’s All in One Promotion Pack, which lets you make international calls, is available for 499 kyats plus 50 kyats per minute, for a 30-day validity period, to Thailand, Malaysia, China, Singapore, Bangladesh, India, South Korea, Japan, Australia, Hong Kong, the US, and Canada. It can be purchased by dialing *2050# or *106#.
Voice call packages can be purchased by downloading the MPT4U app from the Google Play Store or App Store, or through mpt.com.mm.
ATOM’s voice call packages, following the recent rebrand from Telenor to ATOM, can also be purchased via the ATOM Store app or atom.com.mm.

ATOM’s international voice call packages are as follows. The Call Like Local package lets you connect with Singapore and India.

Ooredoo users can purchase voice call packages through the My Ooredoo app or via Ooredoo.com.mm. The My Ooredoo mobile app can be downloaded from the Google Play Store and App Store.

Those who purchase the Aumang G package can try their luck at winning data prizes at each level, for a total of up to 1,000 GB. Those who purchase the Doun Doun Doun package can also get a chance to win up to 200 GB.
Ooredoo’s international voice call packages are as follows. The International Call Package covers a total of seven countries: China, Malaysia, India, Singapore, the USA, Canada, South Korea, Japan, and Australia. The IDD Call Pack only covers Thailand and Bangladesh.

Ooredoo users who use USSD codes can find Ooredoo’s list of useful codes at https://ooredoo.com.mm/portal/mm/usefulcodes.
All voice call package information for MPT, ATOM, and Ooredoo above has been sourced from each operator’s respective website and app.