The document can be regarded as the most important and common evidence of parties' allegations in civil actions and non–criminal affairs. The definition, bases, kinds and the conditions of formulation of documents make a part of "substantive law" of evidence whose recognition determines the extent of probative ability of the document. The document that proves the claimant's allegations is basically in his hand. However it is possible in some cases that the document proving the allegation is not in the hand of the person citing it. In this case, in some circumstances, he can ask it to be given.

In the position of the proving the claim or the defense, it can't be cited to any document, but the possibility of the citing requires the document to be "valid". The word of the validity regarding the different concepts of it in the statutes, can be considered under three titles: "validity", "the extents of the validity" and "the documentation capability of the document" all respectively equivalent to these: "the assumption of the originality of the document", "bearing the legal effects of the document subject matter" and "probative capability of the document as an evidence".

The person, against whom the document is cited, in order to defend himself against the document and the prevention of his failure in the action, can select one of these two methods: "substantive defense" and "procedural defense". Procedural defense is possible in three kinds: "denial", "doubt" and "the claim of the forgery". Nevertheless, in addition to this fact that "denial", "doubt" and "the claim of the forgery" are possible to be raised coincidently or constantly, "substantive defense" and "procedural defense" are also possible to be raised coincidently or constantly. In this way, the court should, according to the case, hear one of the defenses raised and ignore the others.

The document given as evidence may, in some circumstances, conflict with other evidence available at the proceedings including testimony, confession, indications, etc. In this case the court must, according to the case, prefer the document or the competing evidence from among the two pieces of evidence and judge on the base of it.