If you want to take n lines of input where each line contains m space separated integers like:
1 2 3
4 5 6
7 8 9
a=[] // declaration
for i in range(0,n): //where n is the no. of lines you want
a.append([int(j) for j in input().split()]) // for taking m space separated integers as inputmatrix = [input().split() for i in range(no_of_rows)] # if only row is given and the number of coloumn has to be decide by user
matrix= [[input() for j in range(no_of_cols)] for i in range(no_of_rows)] # if both row and coloumn has been taken as input from usermatrix = []
n = int(input("Enter the number of row = "))
for i in range(n):
row = []
print("Enter the all values of -", (i+1), "no. row with enter", end='')
for j in range(n):
row.append(int(input()))
matrix.append(row)
print(matrix)
row=int(input("Enter number of rows you want: "))
col=int(input("Enter number of columns you want: "))
mat=[]
for m in range(row):
a=[]
for n in range(col):
a.append(0)
mat.append(a)
for i in range(len(mat)):
for j in range(len(mat[0])):
mat[i][j]=int(input("Input element: "))
print("Your Matrix is :",mat)