Can I use my digital signature / e-sign my Will or use an electronic Will?
No, a Will has to be in writing (not that you must "hand write" the Will, rather for it to be in hard copy and hand signed).
With the Electronic Transactions Act in Singapore, certain documents / contracts can now be e-signed etc. However, Wills continue to be excluded from the application of the Act.
Source: Singapore Statutes Online website
This however, continues to be reviewed and even as recent as 2019, Singapore's Infocomm Media Development Authority (IMDA) has released a consultation paper on that. So who know's how it will go in the future? Till then, grab your pen and sign it!