An affidavit is a written statement which is sworn to be true (an oath). It is signed by the affiant (the person making the oath) and also a notary public or other judicial officer that administered the oath. An affidavit must be made voluntarily and under either a religious oath or an affirmation. It is therefore required to be signed in front of a person commissioned to receive oaths under legislation, eg a solicitor.
You may be required to give a sworn written statement in certain situations. This form contains everything you need to create a general affidavit. Make sure that you sign and swear in front of someone commissioned to receive oaths (eg a solicitor) who must also sign. Swear to a statement of truth using this affidavit template.