The so-called "Reference Intensity Ratio method" (RIR-method) presented by de Wolff and Visser  is used automatically for (semi-) quantitative analysis if at least two entries have been selected as matching. The quantity (weight %) of each selected phase/entry is displayed in the "Quant.(%)" column of the match list and of course also in the report.
Note that the RIR analysis can only be carried out if all matching entries contain I/Ic factors. If only one of the selected entries does not contain an I/Ic factor, the values for the remaining selected entries will not be displayed as well ("n.a." is given in the "Quant.(%)" column of the match list). As an exception, you can activate an option to let Match! use a standard I/Ic factor of 1.0 which might be helpful in some situations.
You should check if an entry contains an I/Ic factor before selecting it, by taking a look at the column "I/Ic" in the candidate list in which a corresponding value must be given.
 P.M. de Wolff, J.W. Visser, “Absolute intensities”, Rep. 641.109 Technische Physische Dienst, Delft 1964.
 Hideo Toraya, "A new method for quantitative phase analysis: Direct derivation of weight fractions from observed intensities and chemical composition data of individual crystalline phases", Rigaku Journal 34(1), 3-8 (2018).