The coefficients are estimates of the population regression parameters in the PLS model. The coefficient matrix (dimension p x r, where p = number of terms and r = number of responses) is calculated from the x-weights and x-loadings.
The coefficients are used with the terms to calculate the fitted value of the response variables. In PLS, standardized coefficients indicate the importance of each term in the model and correspond to the standardized x- and y-variables. You can construct the regression equation for the model using the coefficients.