How is input dataset fed into neural network?

If I have 1000 observations in my dataset with 15 features and 1 label, how is the data in input neurons fed for forward pass and back propagation? Is it fed row wise for 1000 observations (one at a time) and weights are updated with each observation fed or full data is given in terms of input matrix and then with number of epochs, the network learns corresponding weight values? Also if it is fed one at time, what is epochs in that case? Thanks