Do you mean you want a smooth line that goes through all the points? You could fit a spline:
% Set seed for reproducibility
rng default
% The data
x = 1:6;
y = rand(size(x));
% Fit a spline
xq = 1:0.1:6;
s = spline(x,y,xq);
% Plot
figure
plot(x,y,"ko",xq,s,"r--")
If you mean you want to fit some functional form (like maybe a square wave?) to the data, you'll need to give us more info. Also, uploading the data will help.
