I need to get the users ID using the username information through VBScript

I'm not a VBScript expert but according to the API reference the AddUserAccount method (https://www.m-files.com/api/documentation/#MFilesAPI~VaultUserOperations~AddUserAccount.html) seems to return the created user account, so you should be able to get the ID from the UserAccount object (https://www.m-files.com/api/documentation/#MFilesAPI~UserAccount.html).

Thanks for your help!
I have no experience with VBscript, could you send me an example script?

Try with this.

Option Explicit

Dim oServerApp: set oServerApp = CreateObject("MFilesAPI.MFilesServerApplication")
oServerApp.Connect 2, "user", "password", "SERVERNAME", "ncacn_ip_tcp", "localhost", "7766", "DEMO VAULT", false
Dim oVault: Set oVault = oServerApp.LogInToVaultAdministrative(VAULTGUID)

Dim oEmail: oEmail = PropertyValues.SearchForProperty(1089).TypedValue.DisplayValue

Dim oLoginAccount: Set oLoginAccount = CreateObject("MFilesAPI.LoginAccount")

oLoginAccount.AccountType = MFLoginAccountTypeMFiles
oLoginAccount.LicenseType = MFLicenseTypeNone
oLoginAccount.EmailAddress = oEmail
oLoginAccount.Enabled = True
oLoginAccount.UserName = "user-" & oEmail


oServerApp.LoginAccountOperations.AddLoginAccount oLoginAccount, "password"

Dim oUserAccount: Set oUserAccount = CreateObject("MFilesAPI.UserAccount")

oUserAccount.Enabled = true
oUserAccount.InternalUser = true
oUserAccount.LoginName = "user-" & oEmail

dim userid : userid = UserOperations.AddUserAccount oUserAccount

Dim oPropVal : Set oPropVal = CreateObject("MFilesAPI.PropertyValue")

oPropVal.PropertyDef = 1150
oPropVal.TypedValue.SetValue MFDatatypeLookup, userid.ID
Vault.ObjectPropertyOperations.SetProperty ObjVer, oPropVal

oServerApp.Disconnect()

With this script an error occurs when trying to save the Script:

Cliente Novo, StateCondition, 28, Expected end of statement (0x80040008)

dim userid : set userid = UserOperations.AddUserAccount oUserAccount on line 26

Sorry I had put 2 blank lines in my script (I removed Now), the error occurs on line 26 even.
Include your last change and the same error occurred:
Cliente Novo, StateCondition, 26, Expected end of statement (0x80040008)

then try:

dim userid : set userid = UserOperations.AddUserAccount(oUserAccount)

I managed to save the script and when running the message occurred:

Cliente Novo, StateCondition, 26, Variable is undefined: 'UserOperations' (0x80040008)

dim userid : set userid = oVault.UserOperations.AddUserAccount(oUserAccount)

New error: 

RPCDocumentOperationsHelperPrivate.cpp, 9535, Value '80' does not exist, or is a conflict object. (0x800408E8)

The script created the user account and it has this ID. Just failed to set the value on the property.

well in what vault you wanted to create the user? in oVault or in Vault?

Where do you set the id of user? 

Probably this line should be:

oVault.ObjectPropertyOperations.SetProperty ObjVer, oPropVal

well in what vault you wanted to create the user? in oVault or in Vault?

Resp: In oVault.

Where do you set the id of user?

Resp: With this part of the script:

Dim oPropVal : Set oPropVal = CreateObject("MFilesAPI.PropertyValue")
oPropVal.PropertyDef = 1150
oPropVal.TypedValue.SetValue MFDatatypeLookup, userid.ID
oVault.ObjectPropertyOperations.SetProperty ObjVer, oPropVal

Include your last suggestion (oVault.ObjectPropertyOperations.SetProperty ObjVer, oPropVal) and different error occurred:

(0057) (0x80040001)
New Client, StateAction, 31, Object is locked. Try later. Object: 111-34

well in what vault you wanted to create the user? in oVault or in Vault?

Resp: In oVault.

Where do you set the id of user?

Resp: With this part of the script:

Dim oPropVal : Set oPropVal = CreateObject("MFilesAPI.PropertyValue")
oPropVal.PropertyDef = 1150
oPropVal.TypedValue.SetValue MFDatatypeLookup, userid.ID
oVault.ObjectPropertyOperations.SetProperty ObjVer, oPropVal

Include your last suggestion (oVault.ObjectPropertyOperations.SetProperty ObjVer, oPropVal) and different error occurred:

(0057) (0x80040001)
New Client, StateAction, 31, Object is locked. Try later. Object: 111-34

So you are trying to set on oVault, an ObjVer that it is in Vault.

You need to search for the ObjVer from the oVault, than update the oVault.ObjectPropertyOperations.SetProperty ObjVer, oPropVal with the proper ObjVer.

Not really, the property is in the same Vault (oVault), correct the line by putting "oVault.ObjectPropertyOperations.SetProperty ObjVer, oPropVal" and this error occurred:

RPCDocumentOperationsHelperPrivate.h, 2348, O objeto esta bloqueado. Tente mais tarde. Object: 111-34 (0x80040041)
RPCDocumentOperationsHelperPrivate.cpp, 17940, O objeto esta bloqueado. Tente mais tarde. Object: 111-34 (0x80040041)
(M-Files 21.6.10322.8)

(0057) (0x80040001)
(M-Files 21.6.10322.8)

oVault.ObjectPropertyOperations.SetProperty ObjVer, oPropVal

The ObjVer in this statements is the current ObjVer of the document in your Vault.

You need to find the ObjVer in oVault.

Radu Moca, thank you very much for your help and patience, but I couldn't write the script to find ObjVer in oVault.