How to I increase speed of object in my animation?

If you're making a template for Final Cut, then all you need to do is re-time the template in the storyline. Less time will increase the speed, more time will slow it down.

If you want to be able to control the speed of animation inside Motion, you can edit the actual keyframes with the Keyframe editor. You need to select the parameter(s) keyframed to show them in the editor (the editor is accessed by clicking the 3 overlapping diamond shapes just under the lower right corner of the Canvas area (or type ⌘8). The Editor is fairly straight-forward, it will show you the keyframes and you can adjust their parameter amount (vertically) and/or the times (horizontally).

To simplify your retiming needs, usually a behavior is the best alternative to keyframes. The Move behavior is easy to use and the Motion Path behavior is a little more involved. Their retiming "mechanisms" are the same, you simply set in and out points for the behaviors for when you want the animation to begin and end. Shorter durations are faster animations.

Ramp (and Overshoot) give you the opportunity to set parameters for when you want the start and end of the animations to occur without setting "hard" in/out points (or keyframes). The Start and End Values are additive to the current relative position of the object and there are parameters for Curvature (easing) and Acceleration, respectively. Overshoot can put a little (optional) "bounce" at the ends of animations if you like. However, unless you're animating in diagonal lines, you will need to apply separate Ramp/Overshoot behaviors to the X and Y (and/or Z) of the Position parameters.

There is also another way using a "null object" (like a shape that doesn't show - its visibility has been turned off). You can apply a Link behavior to the Position parameter and apply the null object to the Source parameter. Then, apply a Ramp behavior to the Custom Mix. You have access to parameters to control the starting time and ending time of the animation, thus controlling the speed. The null object can be moved anywhere or even *moving* while the animation is occurring and the object animating will always end at the location of the null object:

For this example, the "null object" (outline square - with visibility turned on) is Oscillating vertically. The Circle object Position is Linked to the square. Custom Mix is Ramped over time. Speed is determined by the Ramp > End Offset (which is in #of frames from the end of the Motion Project's length.) [The screen capture shows the "paths" the objects under animation are taking which Motion displays when Show Overlays is On.]

[There are instructions how to set up the Start Offset/End Offset parameters to be represented in "% of Length of clip" in this post: Overshoot Parameter - Apple Community

starting at "Rigging the Start Offset..."]

You have a lot of different options available, all worth exploring!

HTH