OPPO A18 (4GB RAM, 64GB Storage)
Core Specifications:

Display: 6.56-inch HD+ IPS LCD display
Processor: MediaTek Helio G85 octa-core processor
RAM: 4GB RAM
Storage: 64GB internal storage (expandable via microSD card up to 1TB)
Operating System: Android 13 with ColorOS 13.1
Battery: 5000mAh battery with 33W fast charging
Camera Features:

Rear Camera: Dual rear cameras (8MP main + 2MP depth sensor)
Front Camera: 5MP front camera
Design and Build:

Materials: Plastic
Dimensions: 163.8 x 75.6 x 8.2 mm
Weight: 189 grams
Colors: Glowing Black, Lake Blue, Gold
Additional Features:

Connectivity: 4G LTE, Wi-Fi, Bluetooth 5.0, GPS, microUSB
Audio: Single speaker, 3.5mm headphone jack
Sensors: Fingerprint sensor (side-mounted), accelerometer, ambient light sensor, proximity sensor
OPPO A18 (4GB RAM, 128GB Storage)
Core Specifications:

Display: 6.56-inch HD+ IPS LCD display
Processor: MediaTek Helio G85 octa-core processor
RAM: 4GB RAM
Storage: 128GB internal storage (expandable via microSD card up to 1TB)
Operating System: Android 13 with ColorOS 13.1
Battery: 5000mAh battery with 33W fast charging
Camera Features:

Rear Camera: Dual rear cameras (8MP main + 2MP depth sensor)
Front Camera: 5MP front camera
Design and Build:

Materials: Plastic
Dimensions: 163.8 x 75.6 x 8.2 mm
Weight: 189 grams
Colors: Glowing Black, Lake Blue, Gold
Additional Features:

Connectivity: 4G LTE, Wi-Fi, Bluetooth 5.0, GPS, microUSB
Audio: Single speaker, 3.5mm headphone jack
Sensors: Fingerprint sensor (side-mounted), accelerometer, ambient light sensor, proximity sensor
Both models offer a great value for money, with a powerful processor, long-lasting battery, and decent cameras. The main difference between the two models is the internal storage capacity.