There are two types of slot which one will be computable 

https://www.amazon.in/Western-Digital-240GB-Internal-WDS240G2G0B/dp/B078WYS5K6/ref=sr_1_1?crid=3IS1E6PSMKSZN&dchild=1&keywords=m.2+ssd&qid=1602059590&sprefix=m.%2Caps%2C297&sr=8-1

and this type

https://www.amazon.in/Western-Digital-SN550-Internal-WDS500G2B0C/dp/B07YFF3JCN/ref=sr_1_2?crid=3IS1E6PSMKSZN&dchild=1&keywords=m.2+ssd&qid=1602059590&sprefix=m.%2Caps%2C297&sr=8-2

can you suggest best ram and ssd for lap which one will be fast

If you're looking for a fast SSD, that'd be the WD Black line if you want Western Digital.  Samsung makes an extensive line of fast SSDs as well.  The Green WD line are slower drives.

For RAM:  www.crucial.com

what would you prefer Samsung or WD black

It depends on the Samsung model.  As with WD, performance tracks with price, so you can't just compare the brands.  There are multiple levels of performance, which increases with price.

Yeah sure,

Just make sure to check if you have an additional 2 m.2 slots that can expand in NVMe storage.

i bought the ssd and even upgraded it but i only have heatsink for one sd and i dont have the spreader version since my laptop came with one ssd is it a problem if i use the other ssd with out heatsink

You dont really need a heatsink tbh, thats only if you're using the SSD 100% all the time.