How is it possible to extend my visa in Singapore ?

Hi, please how is it possible to extend my visa in Singapore?

If you already have a residence visa and the reasons for granting it are still present, you can get an extension. Ask the issuing authority (ICA or MoM) how to apply for it.
If you are currently on a short-term visa (SVP), you need to apply for a residence visa (and fulfil the requirements). You can read on this forum, or on the ICA/MoM webpages what these are fo the various visa types.
And in case you only want to extend your SVP (up to a maximum of 89 days) and have a valid reason for this, you should approach ICA.