Hello bros,
I would like to create a machine where someone puts a water bottle and then 10 drops of a syrup drop into the bottle after a sensor sensed the bottle.
I have more ideas but this is a first step. I'm very new to arduino, if you could help me figure out what i need to buy and do i would be v grateful 
thanks
Interesting project but we are not a free design or code writing service. We will be happy help out with your design and or code but first you have to make an attempt to design it, write it, post it and explain what is not working properly.
If there is hardware it is always best to post links to technical information as there are many versions of the same or different items. Since we cannot see your project, my eyes are to weak, you need to post using the language of electronics, an annotated schematic, (best) or a clear picture of a drawing. Pictures never hurt. Frizzing diagrams are not considered schematics here, they are wiring diagrams, great for assembly lousy for troubleshooting.
Yes, people will guide you in your project. What do you have so far? Sometimes the hardest question is "What question should I ask?" Start with one question, and little steps will lead to a finished product.
Unless you are mechanically very skilled with a good electronics background, start by looking for a commercial syrup dispenser with a drop counter and sanitary fittings that can easily be cleaned, controllable by logic circuitry.
Do you know where I could find this kind of this thing, where to search? It's almost water like syrup, not very thick.
Find a soft drink bottling facility in your area and ask them the name of the equipment they use.
You will build it.
One idea is a syringe operated by a stepper motor...
That's what research is for!
Hint: start by looking into low-volume precision dispensers.
This concept:
https://www.printables.com/model/188807-arduino-motorized-smt-solder-paste-dispenser
can probably be adapted to dispense syrup rather than solder paste.
Detection of the bottle could be done by many means, but a load cell might be best, IR proximity sensors might not always work for transparent bottles especially if the liquid inside before the syrup is added is clear too. Ultrasonic proximity isn't so good for small areas. Simply detecting the weight of a water filled bottle when put down upon a holder is going to be pretty reliable.
You'll want 3d printing with which to make the more precise physical elements, then maybe something like aluminium T-slot/V-slot profile extrusions (can be cut with a simple hacksaw) to form a larger frame to mount the printed parts to.