its up to you, for my tenants that rent for long time I never update the agreement but if you want to raise rent then better draft a new one and have them pay the extra for deposit and etc

1.

Sign a new TA. If both party agreed to the terms of the 1st TA, then follow. To save on fee, can DIY. Just pay for stamping only.

Retype the agreement and change the relevant dates and monthly rental rate and deposits where applicable. Print 2 sets and sign. To have a Witness for both signatures.

Go to LHDN for stamping within 30 days from date of agreement.

2.

Request tenant to write officially agreeing to continue the tenancy and following the same terms of the 1st TA OR with amended terms where applicable and changing the relevant dates or rental rate. You acknowledge and keep a copy.

No fees applicable.

3.

Verbal confirmation for extension. (NOT RECOMMENDED)
CAUTION ......

No agreement is 100% without dispute whether in writing or verbal during the duration of tenancy.

there are lots of tenancy agreement samples on the internet, just use one of them and edit the contents. I did all my TA myself and bring it to LHDN for stamping after its signed by my tenants. Only cost to me is to print it out and get transportation to LHDN. The cost of the stamping is borne by the tenant. I've always make a 2 years agreement with a clause that they need to stay min 12 months to safeguard their deposit and reduce the times I need to go to LHDN

Draft a new tenancy agreement and make reference to the original one if nothing much has changed. Get it stamped. Just don't go by verbal agreement as you won't be protected if anything happens.

My tenancy agreement extensions has always been a one-pager. Keep it simple.