I bought icloud+ and upload my pictures there. I also use the same apple ID for my macbook too.
You mean you upload from your iPhone? Your Mac will also synchronise your photos if it is signed into your iCloud account AND iCloud Photos is activated. Check this in the Photos app on your Mac: choose Photos > Preferences, then click iCloud.
When i check my photos in my macbook, i see everything I uploaded from my phone
This is how it should work - iCloud unifies your content among the participating devices.
My macbook only has 256GB storage and I bought 200GB icloud plan.
The size of the drive on your device has no relationship to the size of your iCloud plan.
See What's the difference between device storage and iCloud storage?
why [are?] my photos are in my macbook after I logged in my icloud and apple id?
This is how syncing works. iCloud synchronises to all devices.
how can i stop that?
By signing a device out of iCloud Photos if you don't want the photos on that device.
will it take the storage of my macbook’s SSD if i still logging in my icloud?
If you Mac is signed into iCloud it will synchronise - but you can choose to turn on or off separate services; Photos is one of these. See Apple's support document Optimise storage space on your Mac for options of minimising your Mac's use of space. One option is to optimise the size of your photos down to a very small size.
if not plz tell me what to do. I don’t want my photos to be seen in my macbook. I want that just in my icloud.
If you don't want your photos on your Mac turn off iCloud Photos. See the paragraph Stop using iCloud Photos on a Mac
in the support document Use iCloud Photos to store photos in iCloud.
Should i turn on iphone backup? Will that also effect my macbook ssd 256gb too?
Yes, it's convienient to use. Your iPhone will backup to iCloud when being charged and on wi-fi. No, iPhone backups won't be copied across to your Mac. The Backup is for the benefit of the iPhone alone.
