Terahertz (THz) communication technology is considered as one of the key technologies of sixth-generation (6G) communications. The study of THz channel characteristics is the basis for evaluating, deploying, and optimizing THz communication systems. In this paper, we conduct measurements in line-of-sight (LOS) and non-LOS (NLOS) scenarios in an indoor-office scenario at 100 GHz. Based on measured data, path loss (PL) and root-mean-squared (RMS) delay spread (DS) are analyzed and modeled. First, the differences between omnidirectional and directional PL are analyzed. And by analyzing the distance dependence of RMS DS, it is found that RMS DS in the NLOS scenario is negatively proportional to propagation distance while the trend is opposite in the LOS scenario. Second, based on the statistical modeling method, the model parameters of PL and RMS DS are obtained. We compare the obtained model to the 3GPP channel model and analyze their differences. Third, the bit-error-rate (BER) performance of OFDM systems at 100 GHz is simulated based on measured power delay profiles (PDPs). We find that the scenario and propagation distance have an apparent influence on the BER performance. These results can give insight into the design of THz communication systems in the indoor-office scenario.