One of Samus’ most infamous upgrades, the Morph Ball, allows the infamous bounty hunter to curl up into a one-block high ball and move around. This is especially useful for clearing small gaps and traversing vents, and is necessary to complete Metroid Dread. However, unlike in earlier Metroid titles, the Morph Ball isn’t the first ability you obtain.
To acquire the Morph Ball, you first need the Wide Beam upgrade, obtained in Dairon. After getting that, backtrack to Cataris via the shuttle-train and head to the location indicated here for your next boss fight:
This boss fight is similar to the previous one, except two turrets are now blasting in your direction. While not a huge difference in difficulty, you will need to bait out the blaster shots while landing Missile and Charge Beam hits. Make use of your Free-Aim (L Button) as well.
After obtaining the Omega Blaster, you will need to defeat the E.M.M.I. patrolling the area. The long platform immediately outside the boss room is a good place to take it down — bait it towards the left and dash to the right once it commits. Break it’s shielding with the Omega Stream and take it out with the Omega Blaster; make sure to use Free-Aim.
Once you’ve defeated the E.M.M.I. in this area, you will have obtained the Morph Ball. You can use it immediately to get the Varia Suit upgrade next, requiring some small Morph Ball platforming to reach.