On your Samsung Galaxy Note 4, the application "S Voice" is installed. With this app it is possible to perform inputs via voice commands. S Voice can be activated by pressing twice quickly on the home button.
S Voice is a nice feature to control your phone using voice commands, but you will quickly find out that the app is not as good as you want it to have. An example: If you want to send an sms message to an contact by using the voice command, and you have several contacts with the same name in your list, then S Voice doenst choose the right contact.
Anyway, if you want to disable S Voice on your Samsung Galaxy Note 4 on the home button, then you have to do the following procedures:
Open the app menu and then the app "S Voice". After that tap in the upper right at the the three-point symbol. This will now display a small menu. Select "Settings" . In the section "Wake Up" you see the entry "Open via the home key". Remove the check mark in the check box so that S Voice is not opened immediately by pressing the Home button twice.
Finished! You have just successfully disabled the assignment of S Voice on the Home button on the Samsung Galaxy Note 4.