Technically, anyone, not just lawyers, can do a will as long as the will satisfies the required requirements.
See: Guide To Making a Will - Singapore Edition
While the general requirements of the will is simple enough, there are a lot of nuances that can make the will invalid or cause problems. Going to a lawyer is useful when you want to outsource the work and have someone accountable.
See: Pros & Cons of Going to a Lawyer Versus Other Will Provider
But not all lawyers are the same. Some lawyers write a will or do estate planning as a small part of their business and thus, may not be most up-to-date of what could potentially go wrong. At Immortalize, we understand this and try to only include the providers that are the best or provide the services or products as one of their key business so you that can be confident of the competency when choosing any provider on Immortalize.