Append single element to cell array

A = {'a1','a2'};

A{end+1} = 'a3'

  'a1'  'a2'  'a3'

Append multiple elements to cell array (combine / concatenate cell arrays horizontally)

A = {'a1','a2'};

B = {'b1','b2'};

A = [ A, B ]

  'a1'  'a2'  'b1'  'b2'

        replace, merge,...