Adding note records through UI
We can add user notes or note records to NetSuite records such as employees, customers etc. This can be done through NetSuite UI by going to ‘Communication’ subtab and then ‘User Notes’ under the subtab. We can add a new subtab with a title and memo(description) values.
Once a note record is added, it is visible to all users who have access to the record and communication subtab. Therefore note records are very useful to share important remarks or information regarding a record entry. Note records can be removed by clicking the ‘remove’ button at the right end of the note record line under the ‘User notes’ sub-list. This will delete the note record permanently. To see all note records we can use a saved search for record type: ‘note’.

Adding note records via suitescript
We can add note records via suitescript using the record.create() function. Note records cannot be created as a standalone record and a record must be specified on note record creation.
Therefore there is no need of attaching the note record after creation. Please also note that if tried to attach note record to a record it will result in an error. Refer the code to see how note record is created:
//Please make sure 'N/record' module is loaded
function attachNote(recId){
try{
var noteObj = record.create({type: 'note'});
noteObj.setValue({fieldId: 'title', value: 'User note title'});
noteObj.setValue({fieldId: 'note', value: 'User note description'});
noteObj.setValue({fieldId: 'notetype', value: 7});
//note type : 7 stands for hand written note
noteObj.setValue({fieldId: 'customer', value: -2});
//internal id of the record type connected: customer record type:-2
noteObj.setValue({fieldId: 'entity', value: recId});
//Internal ID of the record connected
var noteRecord = noteObj.save();
log.debug("Note record created", noteRecord);
}catch (err){
log.debug("Error found in attachNote() function", err);
}
}