The current flowing in a series circuit is the same everywhere. Figure caption, A series circuit with two bulbs and one cell. The ammeter will read the same at points 1, 2 or 3. In series circuits, ...

Circuit 3: Ammeter on each branch, voltmeter across each bulb Circuit 4: Ammeter on each branch, voltmeter across each bulb Circuit 5: Ammeter on each branch, voltmeter across each bulb Circuit 6: ...