If i have an numpy array like:
x= [[3, 3], [2, 2]]
x= [[3, 3, 1], [2, 2, 1]]
A simple way would be with np.insert

np.insert(x,x.shape[1],1,axis=1)
We can also use np.column_stack

np.column_stack((x,[1]*x.shape[0]))
Sample run 
In [161]: x
Out[161]:
array([[0, 8, 7, 0, 1],
[0, 1, 8, 6, 8],
[3, 4, 7, 0, 2]])
In [162]: np.insert(x,x.shape[1],1,axis=1)
Out[162]:
array([[ 0, 8, 7, 0, 1, 1],
[ 0, 1, 8, 6, 8, 1],
[ 3, 4, 7, 0, 2, 1]])
In [163]: np.column_stack((x,[1]*x.shape[0]))
Out[163]:
array([[ 0, 8, 7, 0, 1, 1],
[ 0, 1, 8, 6, 8, 1],
[ 3, 4, 7, 0, 2, 1]])