Unclear, as I said
(especially this procedure)
I Showed all my blocks, I created a callback function in order to handle the data received via Arduino Nano 33 BLE. I can scan perfectly but I don't receive any data. Please Let me know if I am not clear enough.
Android version & device name?
Did you enable Location in the device settings?
Try this and post screenshot of "Do it" result:
Here are my device properties. I am sorry i didnt understand do you want me to change the block "RegisterForBytes" to ReadBytes? and for my labels I don't have 'Do it'.
Connect your device to Companion, right mouse click on Label1.Text, "Do it".
See also here (point 4): How to ask a question (open new topic)
Okey and replace "RegisterForBytes'' with Read Bytes?
What about trying it first instead of asking more questions and posting the same blocks over and over again. Incidentally, the RegisterForBytes & ReadBytes blocks do not necessarily have to be mutually exclusive.
No.
Why are you getting angry. If you don't want to help then don't as simple as that. I am still learning and If i were an expert in App Inventor I wouldn't ask for help. So take it easy.
I'm not angry at all. I just asked you to try something yourself first. 
Okey You have showed two blocks. i used them just like what you have showed in your image. I can't scan the app, it catches. So I built an apk file and installed it. It's not working i can't receive data.
It's one more time. Were you able to connect to your bluetooth device? I understand that the problem is in the write/read communication itself?
Yes the connection with my app is great. I have showed images iof the scan and the connection.
Try this one:
and post screenshots before & after "Read bytes" button is clicked (of course after scanning & connecting). If you get an error, please post it as well.
PS: UUIDs are saved in TinyDB, so you must enter them only once.
First, download a universal app from the play store to receive ble data. Check in this app if your arduino is sending data correctly.
Yes I use BlueLight, It works perfect. But My app inventor no.
So, show us what your example data looks like?
I guess the solution may be, as Anke mentioned, to use bytes instead of floats. try it. I also see that she has prepared a test app, try it too.
Yes I will try it immediately and show you my results. Thank you so much for your interest in my problem.